| 1. |
- Elfman, Mikael, et al.
(author)
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The Lund Nuclear Microprobe sub-micron set-up. Part III: Sample stage, optical imaging and detector configuration in the experimental chamber
- 2005
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In: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 231:1-4, s. 14-20
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Journal article (peer-reviewed)abstract
- A new sub-micron beamline for high-resolution nuclear microprobe applications has been constructed at the Lund nuclear microprobe facility. The design and construction of the main experimental chamber.. sample viewing system and computer controlled precision sample stage movement is presented in this paper. The chamber is especially designed for using a large area annular HPGe detector. The advantages with such a large area detector are discussed and illustrated. In addition the quality of the optical viewing and the precision sample stage is discussed.
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| 2. |
- Pallon, Jan, et al.
(author)
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Optimization of PIXE-sensitivity for detection of Ti in thin human skin sections
- 2005
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In: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 231:1-4, s. 274-279
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Journal article (peer-reviewed)abstract
- Modern sunscreens contain particles like TiO2 having sizes of 25-70 nm and acting as a reflecting substance. For cosmetic reasons the particle size is minimized. Questions have been raised to what degree these nano particles penetrate the skin barrier, and how they do affect the human. The EU funded project "Quality of skin as a barrier to ultra-fine particles" - NANODERM has started with the purpose to evaluate the possible risks of TiO2 penetration into vital skin layers. The purpose of the work presented here was to find the optimal conditions for micro-PIXE analysis of Ti in thin skin sections. In the skin region where Ti is expected to be found, the naturally occurring major elements phosphorus, chlorine, sulphur and potassium have steep gradients and thus influence the X-ray background in a non-predictable manner. Based on experimental studies of Ti-exposed human skin sections using proton energies ranging from 1.8-2.55 MeV, the corresponding PIXE detection limits for Ti were calculated. The energy that was found to be the most favourable, 1.9 MeV, was then selected for future studies.
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| 3. |
- Shariff, Asad, et al.
(author)
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The Lund Nuclear Microprobe sub-micron set-up. Part I: Ion optics calculation
- 2005
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In: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 231:1-4, s. 1-6
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Journal article (peer-reviewed)abstract
- A new beam line for generating a sub-micron beam spot for high-resolution nuclear microprobe applications has been constructed at the Lund nuclear microprobe facility. In this paper, the first in a series of three, a detailed theoretical investigation of different focusing systems is presented based on calculations performed with the computer programs PRAM and OXTRACE. Comparison is made between a doublet, a triplet, a quadruplet and a split quadruplet (two-stage focusing). For the split quadruplet all four quadrupole magnets were uncoupled. The conclusion from the calculations was that to obtain the smallest possible beam, the two-stage focusing system should be used. Such a focusing system (a doublet at each stage) has been chosen for the new sub-micron set-up at the Lund NMP laboratory. The first stage focuses the beam in an intermediate chamber, which has a high-resolution optical viewing system facilitating more control over the beam spot. This real image of the first stage is then used as a virtual object for the second stage.
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| 4. |
- Shariff, Asad, et al.
(author)
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The Lund Nuclear Microprobe sub-micron set-up. Part II: Beam line, focusing system and scanning
- 2005
-
In: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 231:1-4, s. 7-13
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Journal article (peer-reviewed)abstract
- A new beam line for generating a sub-micron beam spot for high-resolution nuclear microprobe applications has been constructed at the Lund Nuclear Microprobe facility. The design and construction of the beam line, the quality test of the four high precision Oxford OM-52 Quadrupole magnets by the grid shadow method and the beam scanning system are presented in this paper. The beam line is designed for a two-stage focusing system using an independent doublet at each stage. The first stage focuses the beam in an intermediate chamber, which has a scanning system and a high resolution viewing system. The beam spot in the intermediate chamber is then used as the object for the second stage. Slit construction, vacuum system and beam control is discussed. Data illustrating the quadrupole quality and scanning capability are shown.
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| 5. |
- Wegdén, Marie, et al.
(author)
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Hydrogen depth profiling by p-p scattering in nominally anhydrous minerals
- 2005
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In: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 231:1-4, s. 524-529
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Journal article (peer-reviewed)abstract
- Hydrogen has been shown to occur as a trace element in many nominally anhydrous minerals. The presence of hydrogen in several of the major minerals in the Earth's mantle has received attention, due to the possibility that these phases provide a significant hydrogen reservoir. Recently an experimental and analytical procedure for hydrogen measurements in thin mineral samples by proton-proton scattering has been developed at the Lund Nuclear Microprobe facility. An annular surface barrier detector, divided in two insulated halves, is used to detect the scattered proton and the recoiled proton in coincidence. The summed energy of each detected proton pair can be used to produce depth profiles if the individual scattering angles are known. The easiest case is when only a small difference in energy between each detected proton pair is allowed, i.e. scattering angles very close to 45 degrees. This limitation criterion considerably reduces the statistics. For this reason the analytical method has been expanded to use the full detector area (35-55 degrees) and to identify the scattering angles individually for each hydrogen event. Nominally anhydrous minerals, both synthesized and of natural occurrence, with hydrogen concentrations from 10 to 100 ppm have been analysed. Hydrous minerals, as well as Mylar foils were used as standards. Depth profiles show that intrinsic hydrogen can be distinguished from surface contaminations, e.g. water adsorbed on the sample surfaces.
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